Mount for electron discharge devices



' Feb. 1, 1949.

v 'o. FULTON, JR MOUNT FOR ELECTRON DISCHARGE DEVICES Filed Dec. 4, 1946.llllllll-IIIIIL Patented Feb. 1, 1949 FICE MOUNT FOR ELECTRON DISCHARGEDEVICES Oliver H. Fulton, Jr., Montclair, N. J assignor to RadioCorporation of America, a corporation of Delaware 7 Application December4, 1946, Serial No. 714,071

7 Claims.

The present invention relates to electron discharge devices and moreparticularly to improved mounts therefor.

Mounts for electron discharge devices, suitable for use at highfrequencies, are called upon to observe certain structural andpositional requirements of their parts in order to assure goodoperation. The anode and its lead-in represent parts of the mount thatare particularly sensitive to these requirements.

A significant consideration in the design of anodes for use at highfrequencies, is the necessity to provide for adequate heat dissipationtherefrom. To facilitate such heat dissipation by radiation the anode issometimes provided with a large surface, and in some instances providedwith heat radiating" fins. Heat dissipation by conduction is usuallyrelied on to a minor extent and may be effected through the anodelead-in.

Some uses to which electron discharge devices are put, for example insmall-sized devices, do not permit the employment of anodes having largesurfaces or heat radiating fins.- In these applications heat dissipationfrom the anode is to a great extent limited to conduction through theanode lead-in.

Several difficulties are encountered in attempting to effect anefficient heat conduction from the anode through its lead in. As will beappreciated, it is desirable that the heat conduction be uniform on allportions of the anode. The desired uniformity of heat conduction'is notsecured'in some conventional structures in which the anode lead-in isconnected to the anode at a portion thereof substantially centrallylocated transversely of the anode. Such structures result incomparatively good heat conduction fro'in areas adjacent the lead-inconnection, but leaves other areas of the anode exposed to the danger ofoverheating. Furthermore, in small size devices, a relatively largeportion of the anode sur face is exposed to impinging electrons whichimpart their kinetic energy to this surface to generate heat therein. Torequire that this portion of the anode surface also conduct the heataway that is thus generated therein, results in ineificient heatdissipation.

Another important consideration affecting the design of anodes forelectron discharge devices useful at high frequencies is the spacerequirement between the anode lead-inand projecting parts of the inputelectrode to avoid undesired capacity effects there'between. Not onlyshould these elements be spaced from each other far as possibleconsistent with desired operating" 2 characteristics but in addition thearrangement of the lead-ins to the anode and to other electrodes shouldbe such as to render further electrostatic shielding between them, as bya metallic shield, easy to accomplish. In addition the lead-ins shouldbe as short as possible to further reduce capacity effects therebetween.

A further consideration that is presented in the design of anodes foruse at high frequencies, particularly in small sized devices, isassociated with the requirement that the anode possess sufficientmechanical strength, not only to give it a support function in the mountbut also to enable it to Withstand the tendency to buckle under therelatively high temperatures incidental to operation.

While these considerations and the difficulties associated therewithappear to be unrelated and thus suggest distinct treatment, it isobvious that a common expedient fulfilling all of the requirements of ananode and its lead-in for good operation at high frequencies would bedesirable.

It is accordingly an object of the present invention to provide anelectron discharge device having an improved mount structure, and moreparticularly an anode structure having characteristics making itsuitable for use at high frequencies.

It is another object of my invention to provide an anode for an electrondischarge device having a structure which permits substantially uniformheat .conduction therefrom and provides for desired spacing of itslead-in from the input electrode.

A further object is to provide an anode for an electron discharge deviceuseful at high fre quencies which. possesses desirable heat dissipatingproperties, and mechanical strength, and permits desired spacing betweenits lead-in connection and the input electrode to minimize capacityeffects therebetween and to contribute convenience in the employment ofan elctrostatic shielding means.

A still further object of my invention is to provide an anode for asmall sized electron discharge device useful at high frequencies whereinthe surface portion thereof wherein heat is generated during operationof the device, is distinct from the surface portion thereof throughwhich heat is conducted away from the anode.

An additional object is to provide an anode for an electron dischargedevice having a structure which permits the use of a relatively shortleadin conductor.

The inven ion, will be understood best from a detailed description of anembodiment thereof taken in connection with the attached drawing and thescope thereof will be pointed out in the appended claims. In thedrawing:

Figure 1 shows an elevation partly in section of an electron dischargedevice in which the novel anode of my invention is used;

Figure 2 is an elevation of one part of a two-- part anode employing myinvention, the heat generating and heat conducting surface portionsbeing clearly indicated;

Figure 3 is a cross sectional view along the line 33 of Figure 2 andshows the curvature which may characterize my anode;

Figure 4 is a section taken through the line 4--i of Figure 1 lookingtowards the base of the evice and shows the electrode arrangementthereof and particularly the mounted relationship of my novel anodeparts; and

Figure 5 is a section taken through the line 5-5 of Figure 1 lookingtowards the upper part of the device from a plane below that of theleadin conductors and shows the convenient connections of my anode toits lead-in conductors.

Referring now to the drawing in more detail, there is shown in Figure la relativel small sized electron discharge device of the acorn typeemploying my invention. Envelope is having base H encloses an electrodemount including anode part IE or a two-part anode and suppressor grid13. As more clearly shown in Figure l, the envelope also encloses ascreen grid l4, signal grid l5, cathode I6 and second anode part il.Anode parts l2, H are connected to lead-ins i3, is shown in Figure 5,and electrical connection between the 1?;

parts is accomplished by connector 2i].

Insulating spacer plates 2i, 2?. are provided at the ends of theelectrode assembly. Suppressor grid l3 has a portion 23 thereofextending from the surface of spacer 22 remote from the electrodeassembly to shield projecting ear of anode part I2 from a projectingportion not shown of the signal grid and signal grid leadin 34. Portion23 of the suppressor grid has an ear 25 to further contribute to itsshielding 1-:- tion. Suppressor grid i3 is also provided with a lowerportion 26 extending from the surface of spacer 2i remote from theelectrode assembly, to provide an electrostatic shield between anodeleadins l8, l9 and projecting portions 27 of the sly nal grid [5 shownin Figure 5.

The lower portion 26 of suppressor grid i3 is connected to lead-ins 28,29 and to cathode it by wire 30. Heater connections for the cathode areprovided by lead-ins 3!, 32. Screen grid i i connected to lead-in 33.Signal grid 25 is connected to lead-in 34 which enters the envelope ii!at the end thereof remote from base i l. A getter 35 suitably supportedcompletes the device.

In accordance with my invention anode part I2 is of novel constructionto give it desired heat conducting properties and to permit it to bemounted in such relation to the other electrodes as to reduce undesiredcapacity effects between its lead-ins and projecting portions andlead-ins of other electrodes of the mount. This novel struc" ture of myanode is shown in the drawing as applied to a two-part anode forillustrative purposes only. Figure 2 shows one of the parts of atwo-part anode which includes my invention. This anode part is providedwith a tapered edge 36 resulting in end portions 31, 38 of unequallengths. End portion 31 is provided with an ear 24 which may bepositioned centrally of said end portion. End portion 38 is providedwith car 35 adjacent the tapered edge 38. Anode part !2 may be curved asshown in Figure 3 to con tribute added mechanical strength thereto.

Figure 4 shows the relationship of anode part l2 to anode part H. Theconcave surface of the anode parts and their tapered edges are inoppositely disposed relation. Part H is also pro vided with ears similarto ears 25, 01" anode part 12 and corresponding ears on the anode partsare also oppositely disposed. Ears of anode parts l2, ii are received insuitable apertures in top spacer 22, and the ears adjacent the taperededge of the anode parts are received in apertures in bottom spacer 2 i.As shown best in Figure 5, ears 3% are connected to anode lead ins 18,I9.

The provision of tapered edge on my anode parts and the positioning ofears adjacent these tapered edges contributes to good heat conductionfrom the anode and reduction in uncle sired capacity effects betweeninput and output elements of the device. In the particular useillustrated of my invention in a relatively small sized device, thesurface area of the anode is necessarily limited. Therefore, it is notfeasible to rely entirely on radiation for heat dissipation therefrom.The structure of my novel anode therefore is designed to effect heatdissipation from the anode by conduction to a greater extent thanheretofore possible. 1f

That increased heat conduction away from the anode isaccomplished by thenovel structure of my anode will become evident from the followingexplanation. As shown in Figures 1 and 2, the dotted lines on anode parti2 indicate the portion of its surface which is exposed to electronsfrom the cathode. Such electrons strike the surface within the dottedlines and release their kineti energy thereto, thus generating heat inthis surface. A relatively small portion of this heat is radiated fromthe anode and the greater portion must be dissipated by conduction. Asis well known, the conduction of heat proceeds from h temperatureregions of a body to low temperature regions thereof and tends toequalize the temper ature of all regions of the-body. The generaltendency, therefore, is transfer of heat from the portion of the anodewithin the dotted lines to other cooler portions of the anode. There isa relatively small amount of heat that will he conducted to the endportion of the anode due to the smaller areas at these portions that areoutside of the dotted line portion. Therefore, if the ear 39 were placedadjacent the dotted line portion of the anode surface, such as centrallyof end portion 38, conduction of heat through the lead-in to which suchcar would be connected would be inefiicient. Such inefficiency would resuit from the fact that very little heat would be directly conductedfrom the dotted portion of the anode surface to such lead-in due to thehigh temperature of such portion which would oppose heat transfertherethrough. Heat transfer from the edge portions outside of the dottedportion to the lead-in would also be inefficient since the heatedportion remote from the lead-in would have to traverse intermediateportions 01" high temperature.

As shown in Figure 2, the novel structure of my anode provides for theefficient conduction of heat from the dotted line portion of the anodeto'the ear 39' connected to a lead-in. As the arrows indicate, heat isconducted from all longitudinal portions of the dotted line enclosed surface portion of the anode to the ear 39 and consequently to the lead-into which it is connected. The tapered form of the anode provides agradually increased area from end 31 to end 38 for heatconduction.Therefore, the heat conducted from difierent portions of the heated areawithin the dotted lines follows distinct paths through the tapered sideportion of the anode to the ear and the lead-in to which this car isconnected. There .thercfcre, a temperature gradient from each transverseportion of the area within the dotted lines and the heat dissipating ear39 of the anode. This results in a uniform conduction of heat from allportions of the heated area and contributes to good operation of thedevice in which my novel anode is used.

In the embodiment illustrated-the mount is supported on the lead-inswhich extend radially through the envelope wall. The lead-ins thereforehave a substantial cross sectional area to enable them to perform theirsupporting function. It will be noted from Figure 5, that my novel anodestructure permits direct connections between ear 39 thereon and thelarge cross sectioned lead-ins IS, IS. I-Ieat from the anode is,

therefore, transferred directly to these lead-ins through which it isconducted to external heat dissipation means, not shown.

From the foregoing it will be appreciated that the combination of thetapered edge 36 and the protrudin ear on the wider end 38 adjacent thetapered edge For connection to a lead-in results in efiicient heatconduction from the anode. In addition, the disposition of ear 3!!adjacent the tapered edge 36 also contributes to a desired arrangementof the lead-ins to the anode and to other electrodes of the device.Thus, as will appear from Figure 5, anode leads l8, l9 may be of reducedlength since the wider end 38 of the anode and the ear 39 thereon extendtoward the envelope wall and the lead-ins. This reduced length of thelead-ins I8, I9 contributes to a reduction of undesired capacity effectsbetween these lead-ins and lead-ins serving other electrodes orprojecting portions of other electrodes extending below bottom spacerI8.

Not only does the structure of my anode permit the use of shorterlead-ins, but the portion represented by ear 39 to which the lead-insare connected is displaced a desired distance from other elements of thedevice. This further aids in reducing undesired capacity effects in thedevice.

Furthermore, the spacing between the anodelead-in connections and otherelements of the device provides a convenient space within which to mounta metallic electrostatic shield, to further reduce capacity efiectsbetween input and output elements of the device. Thus a U-shapedmetallic shield 25 may be interposed between anode lead-ins 58, IS onthe one hand and the cathode heater and screen grid lead-ins 3|, 32, 33and projecting portions 2'! of the signal grid on the other hand. Theend of the shield 26 adjacent the anode lead-ins I8, I9 is closed, sincethese lead-ins are not required to enter the enclosure of the shield.However, the end of the shield remote from the anode lead-ins I8, I9 isopen to permit entering of leads to the screen grid and cathode heater,the projecting ends of which are enclosed by the shield.

The structure of my novel anode also contributes to its mechanicalstrength. Thus the additional metal body provided at one end addsrigidity to the anode. If desired, the anode may be curved as shown inFigure 3 to add to its mechanica-l strength, although my invention doesnot require it.

While my invention has been described in connection with a two partanode employed in a small sized acorn type tube, it is not intended thatit be limited thereto. For example, a single part anode may include myinvention. Neither do I wish to be limited to a straight tapered edge asshown in the drawing. Edge 26 may be curved or stepped to provide thedesired gradient of heat conduction without departing from theinvention. Although the invention finds particular usefulness in smallsized devices, it can also be employed in larger devices to advantage.Therefore I desire to include the foregoin and other modifications whichmay suggest themselves to persons skilled in the vart Within the scopeof the invention as pointed out in the appended claims.

I claim:

1. An electron discharge device having an anode and a cathode, anodehaving a surface for receiving impinging electron" from said cathodewhereby heat is generated in aid anode, and means for efiicientlyconducting heat from said anode, said means comprising a progressivelyincreased lateral extension of said anode from one end thereof to theother whereby one end of said anode is wider than the other thereof, anda lead--in connected to said anode at said wider end thereof.

2. An electron discharge device having an anode and a cathode, saidanode having a surface for receivin impinging electrons from saidcathode, whereby heat is generated in said anode, and means foreiliciently conducting said heat from said anode, said means comprisinga progressively increased lateral extension of said anode from one endthereof to the other, whereby one end of said anode is wider than theother end thereof, and a lead-in connected to said anode at said widerend thereof eccentrically with respect to the longitudinal axes of saidanode.

3. An electrode for a high frequency electron discharge device forintercepting electrons, said electrode having a different crosssectional area at axially displaced locations thereon, said crosssectional area being greatest at one end of one dimension of saidelectrode, one edge of said electrode extending in said one dimensionparallel to the longitudinal axis thereof, the opposite edge of saidelectrode extending angularly with respect to said one edge, and a leadfor said electrode connected to said one end thereof adjacent saidopposite edge, whereby heat from said electrode is efficiently conductedtherefrom through said lead.

4:. A high frequency electron discharge device including input andoutput electrodes, an insulating spacer plate engaging one end of eachof said electrodes for supporting the same in axially parallel relation,said input electrode extending through said plate to a normallyinoperative region of said. device, output electrode having oppositelongitudinal edges spaced differently from the thereof, and a lead-in tosaid output electrode at said end thereof adjacent the one of said edgesspaced farthest from the opposite edge thereof.

5. A high frequency electron discharge device including cathode grid andanode electrodes in axially parallel relation, an insulating spacer havhapertures therein for supporting said elect on one face thereof. saidcathode and grid extending coextensively through said apertures forconnection to lead-ins, an ear on said anode adjacent a longitudinaledge thereof and extending through one of said apertures for connectionto a lead-in, said edge being farther displaced from the lead-in to saidgrid than other edges of said anode for maximum separation of therespective lead-ins serving said anode and grid.

6. A high frequency electron discharge device including anode, cathodeand grid electrodes, an insulating plate for supporting said electrodeson one face thereof, said cathode and grid electrodes extending throughsaid plate to project beyond the opposite face thereof and havingparallel sides, the extending end portions of said cathode and gridbeing laterally spaced from each other to the same extent as the cathodeand grid proper, said anode having diverging sides to provide a largercross section at one end thereof than the other, one of said sides beingparallel to said cathode and grid, said end having the larger crosssection being adjacent said one face of said plate, an ear on said anodeat said one end thereof adjacent an edge thereof, said ear extendingthrough said plate, and lead-ins for said electrodes connected theretobeyond the other face of said plate.

fl An anode ior an electron discharge device having a predeterminedsurface shape for receiving impinging electrons and for uniformlyconducting heat therefrom, said shape being defined by two parallel endsand two angular sides, one of the said angular sides being normal tosaid two parallel endaone of said parallel ends extending laterallyfarther from said one of said angular sides than the opposite end, anear on said one of said parallel ends adjacent the other of said'angularsides, and a lead-in of relatively large cross section connected to saidear.

OLIVER H. FULTON, JR.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,125,317 Ronci Aug. 2, 19382,167,885 Glans Aug. 1, 1939 2,227,025 Schlesinger Dec. 31, 1940

